26 years an Lgv Trainer:
Economical with the truth. ■■?So basically i am a liar
!!!
not a liar, but still wrong (and so is the traffic cop you spoke to )- you can’t make a dual carriageway into a single carriageway by putting cones out !! You would need to remove the grass or barrier in the middle 
(the op didn’t say what the separator was)
The only way the speed limit could drop to 40 was if they put temporary signs out saying 40
Denis F:
26 years an Lgv Trainer:
Economical with the truth. ■■?So basically i am a liar
!!!
not a liar, but still wrong (and so is the traffic cop you spoke to )
The economical with the truth comment was not directed at his assertion the lane closure turns a dual into a single, anyone with an ounce of sense knows that is total ■■■■■■■■, but was questioning whether he really had talked to a traffic cop as I seriously doubt, and indeed hope, no traffic cop would be that stupid.
I’ve never heard of a triple carriageway or even a quadruple carriageway, which would be the case on some roads I know, that are not motorways, The signs on approach are dual carriageway ahead, that is also true for a single-laned dual carriageway (quite rare). And needless to say at the end of the dual carriage way there are signs that indicate this.
blimy some answers so im still none the wiser why i asked the question is that the pontypool hgv test centre leads on to that d/c so it must have confused somebody that day 
Denis F:
not a liar, but still wrong (and so is the traffic cop you spoke to )- you can’t make a dual carriageway into a single carriageway by putting cones out !! You would need to remove the grass or barrier in the middleThe only way the speed limit could drop to 40 was if they put temporary signs out saying 40
My view is that Denis, Coffeeholic and co are right.
The fact that one lane of a dual carriageway is closed, doesn’t mean that is ceases to be a dual carriageway. Thus the speed limit will remain as is designated for that road unless a temporary lower limit is applied for and granted. There has to be signs out to tell drivers of the temporary limit or the limit for that road remains the same.
26 Years…I don’t which Traffic Dept you spoke to mate, but when I wore the white cap of motoring justice, the above was true (and that’s not so long ago!).
Hope that clears it up a bit. Although, I would personally drop my speed just from a safety and courtesy to the workers point of view (you can also maximise the amount of car drivers you are able to ■■■■ off going at 10mph under the limit!).
26 years an Lgv Trainer:
All instructors were told by the examiners. ( If one lane is closed off it becomes a single carriageway Single carriage way speed limits apply )
Then the examiners were also wrong (and not for the first time either).
A dual carriageway is defined as having a physical separation between the opposing lanes. The number of lanes is nothing to do with it.
If lane 1 of a 3 lane motorway is coned off LGVs still can’t use lane 3, because the coned off lane still counts! So even by the incorrect theory, it would still be considered a dual carriageway if one lane was closed.
I love handbags at Dawn 
How does the carriageway separation work on the Aston Expressway? 
Wheel Nut:
I love handbags at DawnHow does the carriageway seperation work on the Aston Expressway?
That is the exception to the rule. Unlike other motorway which have an unbroken central reservation it uses an empty lane as a divider, which explains why the speed limit is less than for a ‘normal’ motorway and is pretty much in line with the limits imposed on motorways when road works mean the central reservation temporarily does not meet the normal criteria.
Coffeeholic:
Wheel Nut:
I love handbags at DawnHow does the carriageway seperation work on the Aston Expressway?
That is the exception to the rule. Unlike other motorway which have an unbroken central reservation it uses an empty lane as a divider, which explains why the speed limit is less than for a ‘normal’ motorway and is pretty much in line with the limits imposed on motorways when road works mean the central reservation temporarily does not meet the normal criteria.
And as if I didnt know before I asked the question, here is the official answer from Wikipedia
In the morning, four of the seven lanes are designated for use by traffic heading toward Birmingham city centre, and two lanes for traffic out of the city. In the evening rush hour, this pattern is reversed and four lanes are made available to outbound traffic and two lanes towards the city centre. At all other times, the road runs with three lanes in each direction.
At all times a central buffer lane is maintained to ensure that traffic does not pass in adjacent lanes. The central lane, used as the buffer when running 3 lanes in each direction, is painted red. Motorbikes are banned from this lane regardless of how it is being used after an accident
And another little quote.
Studies confirmed that a new dual three-lane carriageway was needed to relieve the A38 and to provide for future traffic growth.
Many thanks to our resident font of all knowledge
sorry it was duplicated
Shrek:
…when I wore the white cap of motoring justice, …
Then I should warn you that anything you say can be taken down, twisted around, and used as evidence against you.
Or, anything you say can be taken down and laughed at 
I know that the caution has changed, but the old one was much more fun. 
TBF Shrek, I’m only poking fun at the part that I’ve quoted, I agree with the rest.
“You do not have to say anything, but it may harm your defence if you fail to admit anything when questioned and we later frame you good and proper in a court of law, trussed up like a turkey governor, you’re goin’ dahhhhhn!
Anything you do say may be written down in pencil, rubbed out, f**cked about and generally altered to make you look guilty so we get our figures sorted for the Home Office so we don’t look dumb and incapable (although mostly, we are).”
Is that the caution you meant Dave?
…I know where you live…and I’m good mates with Gene Hunt, so watch it!
You’re kidding, right? Please explain what relevance the number of lanes has to do with whether a road is a dual carriageway or not.
A duel carriageway is denoted by the fact that it is a two way road with a barrier or grass verge dividing the two ways. How many lanes there are on either side are irrelevant.
Then the examiners were also wrong (and not for the first time either).
If for any reason there are special rules temporarily in place and the examiners have been notified about it then there should be a notice pinned up in the waiting room and all instructors informed of this.
Two possibilities here, the police officer you talked to is an idiot and is in serious need of retraining,
Trafic police can be wrong on occasion too.
I did have words with one police officer who objected to us stopping on a duel carriageway to do gear change exersises. He told me I had to stop doing it. iI told him i would not because there were no road markings saying there were restrictions.
He said he did not want us stopping there because we blocked the view of the speed camera
I said drivers should not be speeding anyway so that was their problem not mine…and added that this was the exact place that the examiners held the gear change exersise.
So he went to the test centre and complained - and a notice went us asking us not to use that spot.
I ignored it.
The policeman returned the next day and we had more words.
I told him if he wanted to stop us using that spot he should get yellow lines put there and until then I would continue using it.
Not heard from him since.
Wheel Nut:
How does the carriageway separation work on the Aston Expressway?
It doesn’t. Not as far a it being a dual carriageway is concerned. Whilst it is true that there is a separating ‘closed’ lane along the majority of its length, this lane does not constitute a physical barrier which, on a normal road would result in a speed limit, for trucks, of 40 mph. However, because it is a Motorway, and the speed limit (in general) for trucks on Motorways is 60 mph, they are permitted to travel at the maximum speed limit for the road in question, which is 50 mph.
It’s a similar situation with the Dartford Crossing/Tunnel. Many would view both as being ‘one-way streets’, and therefore single carriageways, subject to a 40 mph limit. However, if one thinks about it carefully, it is a dual carriageway with a physical separation. A bloody big, and wet, physical separation. And probably one of the few sections of dual carriageway in the U.K. never to experience a ‘cross over’ accident.
The definition of ‘Dual Carriageway’ is given by; Section 4 (Interpretation General) of the Traffic Signs Regulations 2002, which says;
‘dual carriageway road’ means a road which comprises a central reservation and ‘all-purpose dual carriageway road’ means a dual carriageway road which is not a motorway;
So the barrier / grass strip in the middle makes the road a Dual Carriageway, not the number of lanes there may or may not be.
Returning to the original question, unless posted otherwise, the limit will be 50 mph for HGV’s. However, the Secretary of State or the Local Authority could impose a lower limit, if they did, signs would have to be erected at regular intervals
Unless the copper was thinking you meant using the cones to separate two lanes, as in a contraflow…